<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    p {
        border: 1px solid gray;
        text-align: center;
    }

    .big {
        font-size: 60px;
        vertical-align: middle;
    }
    </style>
</head>
<body>
        <p>hello <span class="big">world</span> inline formating context</p>
</body>
</html>